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If sin θ = -  35 and &thet...

If sin θ = -  35 and θ lies in the third quadrant, find cos θ

A.

45

B.

- 54

C.

54

D.

- 45

Correct answer is D

Where sin θ = opphyp → 35

opp = -3, hyp = 5

using pythagoras formula 

hyp2 = adj2 + opp2

adj2 = hyp2 - opp2

adj2 = 52 - 32 → 25 - 9

adj2 = 16

adj = 4

cos θ = adjhyp → 45

In third quadrant: cos θ is negative → - 45